26599
I wanna don't want to change the second 9 anymore, since process of elimination is prolly more helpful now that I think about it and 1 hit would eliminate that possibility (in the case of 56789). However, I do not want the pair to be 9s. I notice that there are more higher numbers than lower numbers, so I will change the 9 by 5 to 4.
???49
This will also get a hit in the case of 12345+67890
I do not want to have a 0 or 5 for being on the border, so I will change the 5 by 4 to 1.
??149
Since, I want a pair here, I will change the 6 by 5 to 1.
?1149
That leaves 1 change and since lowering 2 by 1 will make 3 1s, I shall raise it by one leading to 31149
Does that sound reasonable?